(Northern St. Johnswort)
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Facts About this Plant:
- Common Names: Northern St. Johnswort
- Lifespan: Perennial
- Zones: 2 - 6
- Type: Forb
- Bloom Time: July - September
- Status: Native
Hypericum boreale, or Northern St. Johnswort, is native to the northeastern quarter of the US and is adventive in a small area of the Pacific coast. It is a hardy perennial, which grows in wet areas, like ditches, shorelines, along bogs and in swamps and fens. It blooms in mid to late summer with small yellow flowers.
There are over seventy species of Hypericum in the US, most are native, and many look very similar to each other.
This species is one of a group of small Hypericums that overlap somewhat in their range. They can be identified in the following ways:
Hypericum boreale: this species is short, and has oval leaves with a round edge. Its sepals are usually blunt and not tapered to a point. It also sometimes takes on a red tint, but this does not reliably separate it, as the others may do this also.
Hypericum canadense: this species is short and has very narrow leaves, which often have only a single prominent vein.
Hypericum majus: this is a taller, stouter species; it has leaves that are longer and taper to a point, and its sepals taper to a point also.
Hypericum mutilum: this has a very weedy habit; if it gets cut by a mower, it will grow right back and bloom again; its leaves are round and floppy or flimsy, and its flowers do not persist in the sun. It also has blunt, non-pointed sepals.
See the image below for a comparison of the above species. More information will be posted at a later time with a chart for this species group.
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